LEDs have the potential to revolutionize the efficiency, appearance, and quality of lighting. See http://www.energystar.gov/index.cfm?c=lighting.pr_what_are. The United States Department of Energy estimates that rapid adoption of LED lighting in the U.S. could provide savings of roughly $265 billion, avoid 40 new power plants, and reduce lighting electricity demand by 33% by 2027. Thus, the market for LED lighting is expected to grow significantly in the coming years compared to traditional, non-LED based lighting.
As the adoption of LED technology has evolved, lighting controls have become an integral part of the lighting selection process for energy savings and visual comfort. With this increased reliance on controls have come new challenges for lighting designers, specifiers, contractors, and distributors. Consider, for example, a typical lighting fixture that includes a lamp (LEDs) driven by a driver (AC-to-DC converter). The driver is usually configured to operate either with wall switches that provide a step dimming function, a 0-10 V dimmer that provides a more smooth dimming function, or the ubiquitous phase-cut dimmer commonly used with conventional incandescent lights. Existing step dimming drivers, however, are not compatible (i.e., do not operate properly) with 0-10 V dimmers or phase-cut dimmers. Nor are existing 0-10 V dimming drivers compatible with wall switches or phase-cut dimmers, or existing phase-cut dimming drivers with wall switches and 0-10 V dimmers.
The above incompatibility among the different types of dimmable drivers forces lighting specifiers to make sure that the fixtures they select for aesthetics and performance purposes are also compatible with the dimming controls they plan to use in a given room or space. Lighting contractors must also make sure they order and receive fixtures that are compatible with the dimming controls being used for a given project. But as the dimming control systems are not always specified beforehand by the lighting specifiers, or because the specifications sometimes change during a project, the contractors have to keep multiple types of fixtures on hand. Lighting distributors must similarly make sure they carry the correct mix of fixtures that are compatible with the dimming control systems needed by the specifiers and contractors in order to meet compressed deadlines and increased customer expectations. At the same time, the distributors must minimize inventory to avoid being stuck with obsolete products that are based on old technology while LED technology continues to advance and LED fixtures continue to progress.
Thus, a need exists for an improved lighting fixture that is compatible with multiple types of dimmers, and particularly a dimmable driver for such lighting fixture that can operate with multiple dimming protocols.